Fix validation error messages

Author: rafaelsales

lib/doorkeeper/oauth/authorization_code_request.rb

@@ -7,7 +7,7 @@ class AuthorizationCodeRequest
       validate :attributes,   error: :invalid_request
       validate :client,       error: :invalid_client
       validate :grant,        error: :invalid_grant
-      validate :redirect_uri, error: :invalid_grant
+      validate :redirect_uri, error: :invalid_redirect_uri
 
       attr_accessor :server, :grant, :client, :redirect_uri, :access_token
 

lib/doorkeeper/oauth/password_access_token_request.rb

@@ -6,7 +6,7 @@ class PasswordAccessTokenRequest
       include OAuth::Helpers
 
       validate :client,         error: :invalid_client
-      validate :resource_owner, error: :invalid_grant
+      validate :resource_owner, error: :invalid_resource_owner
       validate :scopes,         error: :invalid_scope
 
       attr_accessor :server, :resource_owner, :credentials, :access_token

spec/lib/oauth/authorization_code_request_spec.rb

@@ -59,7 +59,7 @@ module Doorkeeper::OAuth
     it "matches the redirect_uri with grant's one" do
       subject.redirect_uri = 'http://other.com'
       subject.validate
-      expect(subject.error).to eq(:invalid_grant)
+      expect(subject.error).to eq(:invalid_redirect_uri)
     end
 
     it "matches the client with grant's one" do

spec/lib/oauth/password_access_token_request_spec.rb

@@ -44,7 +44,7 @@ module Doorkeeper::OAuth
     it 'requires the owner' do
       subject.resource_owner = nil
       subject.validate
-      expect(subject.error).to eq(:invalid_grant)
+      expect(subject.error).to eq(:invalid_resource_owner)
     end
 
     it 'optionally accepts the client' do